1. Field
Embodiments of the invention relate to the field of cable guides; and more specifically, to devices which contact a plurality of cables moving relative to the device, and change the order of the cables for transmitting forces to surgical instruments intended for use in minimally invasive surgeries.
2. Background
Minimally invasive surgery (MIS) (e.g., endoscopy, laparoscopy, thoracoscopy, cystoscopy, and the like) allows a patient to be operated upon through small incisions by using elongated surgical instruments introduced to an internal surgical site. Generally, a cannula is inserted through the incision to provide an access port for the surgical instruments. The surgical site often comprises a body cavity, such as the patient's abdomen. The body cavity may optionally be distended using a clear fluid such as an insufflation gas. In traditional minimally invasive surgery, the surgeon manipulates the tissues by using hand-actuated end effectors of the elongated surgical instruments while viewing the surgical site on a video monitor.
The elongated surgical instruments will generally have an end effector in the form of a surgical tool such as a forceps, a scissors, a clamp, a needle grasper, or the like at one end of an elongate tube. The surgical tool is generally coupled to the elongate tube by one or more articulated sections to control the position and/or orientation of the surgical tool. An actuator that provides the actuating forces to control the articulated section is coupled to the other end of the elongate tube. A means of coupling the actuator forces to the articulated section runs through the elongate tube. Two actuators may be provided to control two articulated sections, such as an “arm” that positions the surgical tool and a “wrist” the orients and manipulates the surgical tool, with means for coupling both actuator forces running through the elongate tube.
Cables may be used as the means of coupling the actuator forces to the articulated sections because of the flexibility they provide and because of the ability of a cable to transmit a significant force, a substantial distance, through a small cross-section. The actuators may be relatively bulky and it may be difficult to arrange the actuators to couple the applied forces to the cables in the arrangement needed for the cables within the elongate tube. The transition from the arrangement of the cables at the attachment to the actuators to the arrangement at the end of the elongate tube may require the cables to cross over one another to re-order the adjacency of the cables.
In view of the above, it is desirable to provide an apparatus and method for guiding a plurality of cables between actuators and an elongate tube of a surgical instrument intended for use in minimally invasive surgeries that re-orders the adjacency of the cables in a compact and efficient manner.